levin



Jan. 27, 1931. A. 1.. LEVIN RADIO RECEIVQZNG APPARATUS 2 Sheets-Shet 1.

Filed May 22 1925 ,5 ,jra/zrzzzz Z Z 07.31.

Jan. 27, 1931. A. 1.. LEVIN .790.313

RADIO RECEIVING APPARATUS Filed May 22 925 '2 Sheets-Sheet 2 Zlwuentoz Patented Jan. 27,193 1 7 tion of electron tube apparatus-which. does ABRAHAM L; LEVIN, on NEW YORK, N. Y.,'AssIGnoR TOILESTEIN AMER CA, A CORPORATION onnnw YORK;

ooiaPoRATIoN or name RECEIVING APPARATUS I Application filed May 22,

This invention relates tora'dio receiying circuits and more particularly to a construcnot require the employment of primary-and secondary batteries for ts operationii The ob ect of the nvention is to prov de a construction of electron tube Which is particularly adapted for operation from energy supplied from the usual house lighting circuitswithout' the employment: secondary batteries.v

This invention utilizes a construction of electron tube'in which aplurality otinde pendent electrodes are provided, one-of the electrodes I being a heating inelnbfer arranged to be' energized from the lighting circuit. Surrounding the heat ng member there is located aninsulating tubular member on v the outer alls of which is deposited an elec tron emitting'coatingsuch as barium or strontiumor some other-combination of elements having electron emitting properties. Interiorly arranged Within the insulating tube surrounding the heating member there,

is provided a spiral metallic coil'or resistance memher havingits ends passing through the 1 Walls of the insulating tubular member and substantially insulated from the electron emitting coating on the surface of thetubu lar meinbelj Qiie'end of this; coilpasses to one terminal eXter orotthe tube lnl'e the oppositeend ot the coilip'asse's to a plate electrode arranged adjacent the electron em t; gicoating'. ".v lVhile Iha'vesho spiral liars positioned interiorly the insulating tube I desire thatit be understood' th'at'the' position of this coil may he Varied land I 'do not desire to be limited to the particular location of the coil as will be hereinafter dc scribed. A grid electrode 1- control member positi'on'ed Within the tubeadj'a'cei'it ther electron emittingcoati'ng and'in circuit therel with is provided a high resistance, 61 heat internally located Withinhthe' vessel which contains all of the electrodes." I haye'ifound" thatjthisresistance inclose proximityjt'o the control electrode functions to pro duce more uniform operation of the tube. "I he terminails oftl'ie heating member are tron -1 mm side oit'the closed vessel in which the tube of primary or r with thecircu 1925. Serial no. 32,197;

electrodes are contained and are connected across the linecircuit The electron emittingcoating is electrically connected in circuit with one side of the heating member Which defines't-he potential of the electron emitting coatihg as that of one side of the supply line. The plate member is connected through the coil device to the output circuit oft-he system which connectsto the opposite side of the supply line. In this'manner an ltectiye ,dilierenceof potential exists lie- I tween the plate electrode and the electron emitting coating Similarly, the potential existing across the heatinir member is sub stanti ally that which i s delivered by connections from the current supply apparatus.

The tube may be employedina 'i ariety of electrical circuits, but have illustrated the same in connection .Witlia radio receivingcirJ cuit Where the incoming signalling energy is impressed across the input terminals ofthe 'tube The'incoming signalling currents are] virtually impressed across thecircu t exist ingbetiveen the electron emitting coating and the grid electrode. I have termed the elec tron emitting coating the fifth element of my tube COnstructi'on. It will beIobservecltha t.

the electron emission {is not obtained. in the usual n'ianner by actually passing-a heating cin'rent through the electron emitting body,

biitiSpbtained by radiation or electron bornbardinent from the heater member energized as 'l'iereinbei'ore explained flOllL, the houselig'htingfcircuit. The electron emission from the el-ctron emitt ng coating of the fitth element nori'nall'y'talies place in direction to- ,c

ward the plate elect-rode and the internal coil'device "by reason of the factl-of their normal positive polarization from the line circuit. The lnternal coil'clevice by reason;

of its positivejpolarity normally tendstoat":

t-ractthe el'ectron s'ffroin the. heatermember in the direction oftheZfiifth'element there increasing thelho nbardment of the fifth elc-i' ss'cir'cuiti s provided in shunt including the heater member so that hi ghf frequency si gnalling "currents maybe usefully employed only for effecting mentv b-YT the variation 111 electron enii'ssioi'i' from the electron em ttingcoatlng by change invpolar- IQO ity of the grid member. The plate electrode is connected in the output circuit of the tube and may lead to a succeeding tube in cascade arrangement or may have a responsive device connected directly in the output circuit. The difference in potential in the output circuit is substantially that delivered. from the line system as hereinbefore explained.

My invention will be more fully described hereinafter in the following specification by reference to the accompanying V drawings forming a part thereof. and in which Figure 1 is an elementary diagram showing the arrangement of my tube construction in a simplified form of radioreeeiving circuit;

Fig. 2 is a diagrammatic view showing the arrangement of the electrodes of my tube construction;

Fig. 3 is a perspective view of the electron emitting body employed in mytube construction partially broken away to show the interior construction thereof; and,

4 is a view of one of the commercial embodiments of the tube construction of my invention.

Referring to the drawings in more detail, reference character 1 designates a receiving antenna system having a ground system 2 and including a primary inductance 3 in circuit therewith. A secondary winding 4-, is coupled with the primary winding 3 and is tuned by a suitable tuning circuit designatec at 5. For the purpose of more clearly setting forth my invention I have shown in Fig. 1 a. single tube functioning both as a detector and an amplifier of the incoming signalling energy. The tube is represented as enclosed within a vessel 6. Centrally positioned within the vessel I provide a heating member or element 7 having terminals 7a and 77) extending exterior-1y of the tube. Surrounding the heater element I provide the. insulating cylindrical member 8 which may take the form of a tube of glass or other vitreous material. Internally arranged within thetube 8 I provide a coil member 9,

one end of which passes outwardly through the wall of the tube member 8 through an insulating bushing designated at 10 and connects to the plate member 11. The other end of the coil member 9- passes through an insulating bushing 12 and extends exteriorly of the tube to a terminal 14., Upon the exterior of the tubular member 8 I provice an electron emitting coating 15 formed of any suitable material as I have previously described. This material may be a barium or strontium salt or other elements may be used to form a coating directly upon the surface of the insulating tube 8. The heater member 7 by direct radiation or electron bombardment operates to heat the tube 8 and the electron emitting substances 15 produce a constant electron discharge within the vessel 6.

The electron bombardment of the tube 8 is facilitated by the coil 9 which is charged positively with respect to the element attractin g the negative electrons in the direction of the electron emitting coating 15. Coil memher 9 has its turns substantially spaced apart as illustrated for presenting minimum effective area or exposure to the exterior coating 15, while offering substantial attractive force in'nnediately adjacent the heater 7 for facilitating the heating of the insulated tube 8. As has been shown, the plate member 11 presents a large area adjacent the electron emitting coating 15 and thus overcomes any substantial effects of coil 9 upon the electrons from coating 15. The tube 8 serves a shield against any appreciable effects of coil 9 on the electron emission from coating 15. Arranged adjacent the electron emitting coating 15 there is mounted the grid or control member 16 having a resistance element 17 arranged in circuit therewith and interiorly positioned within the tube intermediate the tube and the input treminal 18 thereof.

The power supply for the cathode and anode circuit is either rectified alternating current or direct current. In order to accurately control the energy supplied to the electron tube circuit I intcrpose in the line a pair of substantially equal impedances $34 and 35 variably operative from a single control as designated by reference character 36. To limit the value of the energy supplied to the electron tube apparatus I provide additional fixed impedances 37 and 38 in the line circuit. In order to more fully exclude hum and other undesired interference in the receiving circuit a reactance 39 is connected in the supply circuit. In order to by-pass radio frequency currents, that is, currents of the signalling frequency, I provide a condenser 40 in shunt with the heater member or cathode 7 by which the radio frequency currents may be effectively utilized. The input terminals of the tube are connected in the tuned receiving circuits et 5 with a grid leal: and grid condenser 41 interposed in circuit with the grid member 16. The variations in the signalling currents are impressed directly across the electron emitting body 15 and the control member 16. The plate electrode 11 through the intermediary of. the coil member 9 is connected in the output circuit through terminal 14 and may include any desired form of responsive device 12 or may connect to the input circuit of a succeeding tube of a series and to one side of the current supply line designated at 43. It willbe observed that the electron emitting body 15 is connected through a lead 44 with one side of 7a of the heater member 7. The potential from the current supply system is impressed across the heater member 7 and also across the electron emitting body 15 and the plate electrode 11in suchmannerthat energy in the output circuitrof the apparatus;

member 7.

may be embodied in a number of difierent' forms and. th t I intend no limitations'upon, the invention other than those imposed by the scope of the appended clanns.

electron dischargefrom the electron emitting body 15 tends to take place in the direction of the plate electrode -11." The va'ri'a tion in the signalling energy becomes-'efiecity ot'th'e grid '16 resulting in the control of thde-lectron flow from electron emittingbody 15'toplate- 11 thereby controlling the A clearer conception of the electron'emitng body 15 will be obtained fromthe con rnction illustrated in perspective View in" Fig. 3 of the drawings wherein thetubular member 8 is provided withthe "coating 15 of the electron emitting substance. The coil member 9 interiorly of the tube passes o t,

wardly, as hereinbefore explained, through the walls of the tubular member 8 through bushings 10' and 12 without cont-acting with the electron ehaitting substance 15 and is charged at similar positive polarity as is the plate electrode 11." Bythis arrangement the plate electrode 11 operates to attract electrons from the electron emitting coating 15 while the coil 1nernber9 operates to at tract electrons from the heater 7. The heator member 7 is shown arranged within the tubular member 8.

In the commercial embodiment of the tube construction shown in Fig/lithe leads 18, 7a, 7b and 14. pass downwardly through the base of the tube 17 as represented at 4:5 and connect to a set of four contactson the base of the tube. The tube may be inserted in a standard electron tube socket of the usual bayonet slot type. The electrodes are supported interiorly Within thetube by an inwardly extending portion upon which is mounted the plate electrode 11, the fifth element, or tubular member 8, and the heater bodiments I desire it to be understood that the details of the construction may be Varied without departing from the spiritcf my in vent on.

WVhilel have described my: invention-in 1 certain particularembodiments, desire that it be understood that the principles thereor 'lVhat Iclaim and desire to 'secureQb'j 'Let V tors Patentlof the Unite'dStates is as follows:

1. An electron tube comprising an evacuated vessel, a heater within said Vessel, a,- thimble memberhaving high electrical resistivity and good heat conductivity surroundln said heater, a Winding haV-in'gits turns lying in contact with the interior Walls of saidinsulating member and having connec-' tions whereby it may be electrically charged I have de-signatedthe grid 16 to 'e'ffectrbombardment of electrons from said heaterraidally toward said insulatingmenr her, an electron emitting coating carried by y the exterior Walls of said member and grid tive to vary the degree of charge and polar-Q andplate electrodes within saidvessel, said grid and plate electrodes being arranged 'to' control the bombardment of saidplate elec- 1 within saidyesseha thimble member enclosing said heater said thin'ible member cont prising insulatlon material having'high-heat conductivity, a coil member having its turns iwound in contact with the interior wallsof said thimble and having connections whereby it may be electrically charged to attract electronic bombardment from said heater radially in the direction ofsai d thimble for rais .ing thetemperature thereof, an electron emitting coating extending over'the exterior walls I of said thimble and grid and'plate electrodes within said vessel, said grid electrode operating to control the bombardment of electrons from f's'aid electron 1 emitting coating against said plateelectrode. v

" 3.- An electron tubecomprising an evacuated Vessel, a heater, an insulating thimble' enclosing said heaterjsaid thimble having a high degreeof heat conductiv ty. a multiple turn coil'hav ng its turns wound in contact With the interior walls of said. thimble and diWlIlg connections whereby it may be electrically charged to attract electronic bom} bardment from saidheater radially in the direction of said tubular member for raising the temperature thereof, an electronemitting coating carried upon the external walls of said thimble, and grid and plate electrodes disposed adjacent the electron emitting coatingon said thimblewhereby electrons emitted by said electron emittmgcoating may be 'di rected against said plate'electrodeand the of said grid electrode.

bombardment thereof yaried under control ated vessel, heaterwithin saidyessehan insulated tubular member substantially in the form of a thii'nble surrounding said heater and'haying anjelectron emitting coating thereon, grid and plate electrodes within sald- Vesselarranged ad acent sa1d electron emitting coating and a coll member disposed within said tubularnieinber'and series connectedywith, saidfplate'electrode, said coilmember operating at a potential more positive-than said heater while said plate operates potential inorepositive than the-electron v emitting coatingon said tnbular inemberc 5; An electrontube comprising an evacn 'atedWesseL-a heater Within saidvessel, an insulated cylindrical member substantially in theformj of athimble surrounding said heater, anxelectr'on emitting coating 'on the 7 4. An electron tube comprising an evacnexterior walls of said cylindrical member, a grid and plate electrode adjacent said electron emitting coating within said tube, a grid terminal, a plate terminal, and a coil member disposed within said cylindrical member and connected in series between said plate electrode and the plate terminal of said tube, said coil member having its turns contacting with the interior walls of said cylindrical member. v

6. An electron tube for operation from relatively 'high potential comprising an evacuated vessel containing a heating element, a heat conducting envelope substantially in the shape of a thimble surrounding said heating element, an. electron emitting coating on the exterior walls of said envelope, a control electrode, a plate electrode, and an electrode disposed concentrically within said heat conducting envelope surrounding said heating element and separated from said electron emitting coating by the walls of said envelope and electrically connected with said plate electrode, said concentrically disposed electrode having substantially less exposure to the electron emitting coating on the exterior Walls oi? said envelope than the exposure of said plate electrode with respect to said coating whereby electrons emitted by said heating element are caused to bombard said heat conducting envelope for raising the temperature thereof and developing electron emission from said electron emitting coating, said emission being directed toward said plate electrode.

7 An electron tube comprising an evacuated vessel, a heating member therein, an envelope of heat conducting material substantially in the shape of a thimble Slll":

rounding said-heating member, an electron emit-ting coating on the exterior walls of said envelope, a plate electrode within said vessel adjacent said electron emitting coating, a control electrode within said vessel adjacent said electron emitting coating and a coil member interiorly of said envelope and electrically connected with said plate electrode, said coil member having connections whereby it may be electrically charged for facilitating bombardment of said envelope by electrons from said heating meman evacu by the interior walls of said envelope and having less exposure with respect to said electron emitting coating than the exposure of said plate electrode with respect thereto, said coil member being electrically connected to said plate electrode for causing electron bombardment of said heat conducting envelope for producing secondary emission therefrom.

[9. An electron tube comprising an evacuated vessel, a heating element within said vessel, aheat conducting envelope surrounding said heating element, an electron emitting coating on said envelope, grid and plate electrodes within saidevacuated vessel and a spiral member within said heat conduct ing envelope electrically connected to said plate electrode and having less exposure to said electron emitting coating than the exposure of said plate electrode with respect thereto whereby electrons emitted from said heating element eiiect secondary emission of electrons from said electron emitting coating for bombardment of said plate electrode.

In testimony whereof I aiiix my signature.

ABRAHAM L. TJEVIN. 

